Inconsiderate bosses not only make work stressful, they may also increase the risk of heart disease for their employees, experts believe.
A Swedish team found a strong link between poor leadership and the risk of serious heart disease and heart attacks among more than 3,000 employed men.
And the effect may be cumulative - the risk went up the longer an employee worked for the same company.
The study is published in Occupational and Environmental Medicine.
Experts said that feeling undervalued and unsupported at work can cause stress, which often fosters unhealthy behaviours, such as smoking, that can lead to heart disease.
Previous work has shown that unfair bosses can drive up their employees' blood pressure, and persistent high blood pressure can increase heart disease risk.
For the latest study, researchers from the Karolinska Institute and Stockholm University tracked the heart health of the male employees, aged between 19 and 70 and working in the Stockholm area, over a period of nearly a decade.
During this time 74 cases of fatal and non-fatal heart attack or acute angina, or death from ischaemic heart disease, occurred.
All the participants were asked to rate the leadership style of their senior managers on competencies such as how clearly they set out goals for their staff and how good they were at communicating and giving feedback.
Feeling undervalued and unsupported can cause stress, which often leads to unhealthy behaviours...adding to your risk of developing heart problems
Cathy Ross of the British Heart Foundation
The staff who deemed their senior managers to be the least competent had a 25% higher risk of a serious heart problem.
And those working for what was classed as a long time - four years or more - had a 64% higher risk.
The findings held true, regardless of educational attainment, social class, income, workload, lifestyle factors, such as smoking and exercise, and other risk factors for heart disease, such as high blood pressure and diabetes.
The researchers, which included experts from University College London in the UK and the Finnish Institute of Occupational Health, said that if a direct cause and effect was confirmed, then managers' behaviour should be targeted in a bid to stave off serious heart disease among less senior employees.
They said managers should give employees clear work objectives and sufficient power in relation to their responsibilities.
Cathy Ross, cardiac nurse for the British Heart Foundation, said: "This limited, male-only study suggests that a good, clear working relationship with your manager may help to protect against heart disease.
"Feeling undervalued and unsupported can cause stress, which often leads to unhealthy behaviours such as smoking, eating a poor diet, drinking too much alcohol and not getting enough exercise - adding to your risk of developing heart problems.
"Being fit and active can give you the double benefit of busting work stress and boosting your heart health at the same time."